PUERTO AYORA, Ecuador -- Marauding Europeans are nothing new to the Galapagos Islands, which long ago were the haunt of English pirates preying on Spanish galleons laden with Inca gold.

But Ecuador, which owns the archipelago, may soon have to take action against menacing outsiders, realizing foreigners with cameras are every bit as dangerous as those with cutlasses.

Ecuadorean President Rafael Correa, a leftist who prides himself on putting principle before profit, is mulling whether to restrict tourist licenses to the volcanic outcrops, home to tiny penguins, marine iguanas and venerable giant tortoises.

Victor Carrion, deputy director of the Galapagos National Park, went one step further, saying Ecuador should rethink its strategy for the islands whose finches inspired British naturalist Charles Darwin's theory of evolution.

"We have to revise our tourism model and aim for fewer tourists and higher revenues," he said. "We have not set a cap on tourists, but I think we should."

When the Beagle sailed into the Galapagos Archipelago in September 1835, Darwin found an almost pristine "little world within itself."

Now, four flights packed with tourists touch down in the Galapagos every day. The annual number of travelers has doubled in five years to 145,000 and grows nearly 12 percent every year.

BEACHES VERSUS BOOBIES

Internet cafes, trendy hotels and restaurants litter the main port, Puerto Ayora, where scores of tourists in beachwear mingle with blue-footed boobies and gray iguanas, perched on jagged rocks jutting out into the turquoise waters.

Pick-up trucks loaded with tourists roar down highways, while bright red crabs cower at the roadside.

The United Nations earlier this month said Ecuador should step up efforts to protect the Galapagos from growing tourism and immigration. It will decide next month if the Pacific archipelago is officially "in danger."

The Galapagos, 625 miles (1,000 km) off Ecuador's coast, are the country's No. 1 visitor attraction. Tourism earned $486 million last year and is the fourth largest source of income after oil, bananas and fishing.

Martin Wikelski, a biology professor at Princeton University, said one of the main threats was posed the number of mainland workers lured to the islands for the tourism industry.

"They are bringing other species that can out-compete natives," he said.

The immigrants hide out in shantytowns and dimly lit hostals, similar to those on the mainland.

"I try not to stay out at night... police and union workers are sometimes on the lookout for migrants like us," said Hector Montachano, a peasant from the Andes.

The need for cheap labor to build hotels and restaurants and work as cleaners on cruise ships has attracted thousands of migrants from the poor mainland, causing grave environmental problems with animals they import from the Andean highlands.

Galapagos park rangers have launched a cull of goats, shooting them down from helicopters, backed up by imported hunting dogs on the ground, after migrants' goats were found to be competing for food with the archipelago's giant tortoises.

Rats brought in by ship and pigs brought in by workers from the mainland have also upset the island's delicate balance.

DO TURTLES NEED TOURISTS?

Rocio Martinez, president of the Galapagos' chamber of commerce, said tourism was crucial for the islands' survival and that construction and development there had been exaggerated by outsiders and some government officials.

"Progress on the Galapagos is based on tourism," she said. "We should take advantage of our natural environment to reap the benefits of tourism."

She said most visitors stayed on board cruise ships that take them to designated locations around the island, reducing the tourists' interaction with animals.

Princeton biologist Wikelski agreed the successful formula would be a balance between tourist revenues and ecology.

"If there is good, well-regulated tourism, it is valuable for Ecuador and for the islands. It will just increase the price," he said.

However, Fernando Ortiz, head of Conservation International in the islands, said action was needed to stop quick profiteering among tourist operators.